UNIT 9

HYPERTEXT

9.1 Concept

• The concept of hypertext was very important for the creation of the World Wide Web.
• By using textual links, Web pages written in HyperText Markup Language (HTML) can be linked and cross-referenced throughout the Web.
• It is a text that links to other information.
• By clicking on a link in a hypertext document, a user can quickly jump to different content.
• Software programs that include dictionaries and encyclopedias have long used hypertext in their definitions so that readers can quickly find out more about specific words or topics.

9.2 Open Document Architecture (ODA)

The Open Document Architecture (ODA) is an the world over standardized digital representation for file content material and structure. ODA has been ratified by using the International Standards Organization as ISO 8613.

ODA is a crucial standard for each person who desires to share files with out sacrificing manipulate over content material, shape and format of those files. It is designed to remedy difficulties created by the variety of record formats that exist. An ODA record may be opened changed, exchanged, saved and reproduced by means of any ODA-compliant program.

The cost of ODA increases with time. That is, at the same time as proprietary stored documents may be incompatible with the new formats of software program upgrades, ODA documents remain readable regardless of recent formats. With ODA, big document conversions turns into a factor of the past.

ODA not only protects workplace automation investments, it also lets in for easy document transfer and common report storage. Moreover, ODA goes past unformatted textual content by using the usage of logical shape, so that text may be formatted on output in a form maximum appropriate for the output tool.

ODA has established subsets of functionality, appropriate for precise packages. Such a subset is specified in a practical profile or Document Application Profile (DAP).At present, functional profiles for ODA have been developed for three specific sorts of use.WordPerfect Exchange, the ODA answer from WordPerfect, the Novell Applications Group, helps a profile called FOD26. This DAP pursuits to provide aid for typical word processing and easy Desk Top Publishing.

Who needs ODA?

Working with phrase processors has grow to be a natural a part of state-of-the-art office life for maximum of us. Word processors, editors and other file handlers offer digital assistance inside the production of files, which often encompass graphics and pictures as well as text.

The story could be very exceptional where file handling is concerned; it is still not possible for us to send electronic documents to other humans without first having to inquire approximately their document managing facilities. Is there in reality no opportunity to sending all our texts in ASCII form?

What is wanted is a single, self-contained popular below which documents, including each text and photographs, may be transmitted with all attributes intact from one device to another, for further editing, processing, storing, printing and Open Document Architecture (ODA) is exactly such a preferred.

The Open Document Architecture and Interchange Format (ODA/ODIF) is a brand new compound popular for use in the increasing world of open systems.Compound, or multimedia files are those made up of several special varieties of content; for example, individual text, photographs and pics.

In the early 1990s, six foremost computer groups joined together to form the ODA Consortium.The ODA Consortium (ODAC), a European Economic Interest Grouping, promotes the ODA preferred and offers manner to put in force it in software packages by means of use of Toolkit APIs.

The groups are: Bull SA, DEC, IBM, ICL PLC, Siemens-Nixdorf and Unisys. In 1994, WordPerfect, the Novell programs group joined the consortium.

Why use ODA?

ODA has been designed to facilitate inter-operability between unique report processing systems. Document interchange occurs every time one person sends a file to another. Users can also prefer digital file interchange for a whole lot of reasons:

• The pace of transmission can be quicker

• Electronic distribution is extra efficient, if there is a couple of recipient • The recipient may also wish to keep the report in a retrieval gadget

• The recipient may also desire to make similarly adjustments to the document before it reaches its final shape, or use excerpts from it in other files

• The report may contain statistics of a nature which is not able to being rendered Voice The essential gain inside the context of file interchange is to provide the document seller independence.

Because ODA has been designed to be extensible, the ODA wellknown is written to have a completely large scope. In practice, however, no device can aid every possible feature.How then is it viable to guarantee that the sender and the recipient of a report aid a well suited set of features?

The answer to this trouble is a fixed of defined file application profiles (DAP). These are arranged in levels of increasing functionality. Loosely speaking, each DAP defines a listing of supported features, which any device at the equal or better level must be able to be given or interpret correctly.

How does ODA work?

ODA prescribes, first of all, an organization for the information in a document. This is divided into the following categories:

• Logical structure: --> Like SGML, a sequential order of objects in the file.
• Layout: --> The placement of content on the page
• Content: --> Text, geometric graphics, and raster graphics (raster graphics are also called facsimile images)

For example, a memo document (where layout may not be critical) could have logical and content components in ODA format.

All ODA files can be classified as Formatted, Formatted Process able, or Process able. Formatted files are not to be edited. Process able and Formatted Process able files can be edited.

• Formatted: --> content and layout
• Process able: --> content and logical
• Formatted Process able: --> content, logical and layout

9.3 Multimedia and Hypermedia Coding Expert Group (MHEG)

The improvement of MHEG arose directly out of the growing convergence of broadcast and interactive technologies. It specifies an encoding format for multimedia packages independently of provider paradigms and network protocols. Like QuickTime and OMFI it's far concerned with time-based media gadgets, whose encodings are decided by way of other standards. However, the scope of MHEG is bigger in that it directly helps interactive media and real-time transport over networks. There were progressions of MHEG requirements (similar to MPEG) the current sizeable trendy is MHEG-5 however drafts standards exist as much as MHEG-7. Every design usually represents a compromise between conflicting goals. MHEG's design is no exception, mainly if you don't forget that MHEG-five (and later) objectives a continuously developing and fiercely aggressive marketplace where broadcast and interactive technologies converge nearly Converging technologies have regularly stimulated adopting popular solutions. Multimedia packages requirements offer extra than just the plain objectives of portability and interoperability. A accurate multimedia trendy can emerge as a reference answer for device builders and alertness programmers. It also promotes the usage of modular architectures that rely on commonplace additives that accomplish a selected functionality, such as interpreting and providing MHEG applications to users. This undertaking is carried out with the aid of a compliant runtime engine (RTE), a resident software aspect that schedules transport of an software to the user. It's aimed toward a wide set up base within complete solutions, like a Video on Demand or an Interactive TV machine.RTEs help enhance a product's go back on investment, abate a product's consistent with unit costs, and offer high quality, robust products due to massive product checking

The family of MHEG standards

MHEG encompasses the family of standards issued by the ISO/IEC JTC1 joint technical committee's working group WG12�information technology subcommittee SC29, coding of audio, picture multimedia, and hypermedia information. See Table 8.1 for the complete list of MHEG standards.  

Since it was added first, MHEG-1 obtained It's the generic widespread for encoding multimedia objects without specific assumptions on the utility place or on the target platform used for delivering and rendering these gadgets to the MHEG-three offers a script extension to MHEG-1. MHEG-four specifies a registration technique for identifiers used by the gadgets to identify, for example, a specific layout for content material data. MHEG-five can conceptually be considered a simplifying profile of MHEG-1.It addresses terminals with restricted resources, just like the set-pinnacle unit. Actually, an MHEG-1 decoder cannot decode MHEG-5 programs due to a few slightly special provisions added to optimize performance in VoD/ITV environments. MHEG-6 extends the declarative MHEG-five approach with procedural code skills standard of a scripting language.It defines the interface (MHEG-five API) and a script engine's runtime surroundings on pinnacle of an MHEG-5 engine the usage of the Java virtual gadget to offer a entire answer for application illustration. MHEG-7, a new fashionable, addresses the conformance and interoperability of MHEG-five engines and packages.

9.4 Standard Generalized Markup Language (SGML)

Standard generalized markup language (SGML) is a text markup language that serves as a superset of widely used markup languages like HTML (hypertext markup language) and XML (extensible markup language). SGML is used for marking up documents and has the advantage of not being dependent on a specific application.

9.5           Document type Definition (DTD)

Executive overview

DTD grammars are a fixed of policies that define

1. A fixed of elements (tags) and their attributes that may be used to create an XML report;

2. How those elements may be combined/embedded ;

3. Different kinds of entities (reusable fragments, special characters).

DTDs can not define element content material types, i.E. What text can go interior elements. Most characteristic can not be typed either. For example, with a DTD one can not specify that input have to be a number of from 0 to 100.. XML Principles recalled Specification of a markup language There are many approaches of defining a XML language. You may want to write down the specification of an XML vocabulary in easy prose, or use a so-referred to as Schema language, or finally, a combination of the two. The most simple schema language, i.E. DTDs, is defined inside the XML Standard.

DTD stands for Document Type Definition. A DTD is a hard and fast of regulations that represent a grammar (also referred to as schema) that defines the so-referred to as XML utility also known as XML vocabulary. For example, the record xhtml1-transitional.Dtd to be had at thru the XHTML 1.zero specification page, officially defines the grammar for the XHTML 1 web markup language.

• The maximum important part of a DTD-based totally markup language is typically the DTD itself, but further other constraints may be introduced in a design report.

• The DTD does now not become aware of the root detail! You will have to tell the customers what elements can be root elements.

• Since DTDs cannot express information constraints, write them out in a specification document, e.G. "the value of period attribute is a string composed of various plus "cm" or "inch" or "em".

Examples:

<size length="10cm">

<size length="3inch">

Example 1: A simple DTD

<!ELEMENT page (title, content, comment?)>

<!ELEMENT title (#PCDATA)>

<!ELEMENT content (#PCDATA)>

<!ELEMENT comment (#PCDATA)>

A DTD document contains just rules and no XML declaration is needed ... More details later...

Associating a DTD with an XML document

Before we learn how to create our own grammars, let's shortly recall how to associate a DTD with an XML file. 

• In the XML file, you can add that of a declaration that specifies the DTD and that implicitly requires to that of the XML contents which must be validated.

•  on top of the file DTD file is declared after the XML declaration.

• XML declarations, DTD declaration etc. are the part of the prologue

Example XML contents with a DTD declaration  <?xml versi ?>

<!DOCTYPE hello SYSTEM "hello.dtd">

<hello>Here we <strong>go</strong> ... </hello>

Let us recall from the editing XML tutorial, that there are four ways of using a DTD

(1) No DTD

• XML document will just be well-formed, or validation takes place in some other contexts, e.g. There exist tools that allow you to find out if a given XML document is valid with respect to a given DTD file)

(2) DTD rules are defined inside the XML document

• We get a "standalone" document (the XML document is self-sufficient)

(3) "Private/System" DTDs

• As shown in the example above, the DTD is located on the system (own computer or the Internet). That's what you are going to use when you write your own DTDs.

(4) Public DTDs

• we use a name for the DTD. This means that both your XML editor and user software know the DTD. This is the strategy used for common Web DTDs like XHTML, SVG, MathML, etc.

Finally, let us recall that other schema formalism than DTDs exist, e.g. XML Schema.

Sample XML documents with DTD declarations Example 1 - Hello XML without DTD  <?xml versi standal?>

<hello> Hello XML et hello cher lecteur ! </hello>

Example 2 - Hello XML with an internal DTD   <?xml versi standal?>

<!DOCTYPE hello [

<!ELEMENT hello (#PCDATA)>

]>

<hello> Hello XML et hello dear readers ! </hello>

Example 3 - Hello XML with an external DTD

That's what you should with your own home-made DTDs  <?xml versi ?>

<!DOCTYPE hello SYSTEM "hello.dtd">

<hello> This is a very simple XML document </hello>

Example 4 - XML with a public external DTD (RSS 0.91)  <?xml versi "?>

<!DOCTYPE rss PUBLIC "-//Netscape Communications//DTD RSS 0.91//EN"

"http://my.netscape.com/publish/formats/rss-0.91.dtd">

<rss versi>

<channel> ...... </channel>

</rss>

9.6 Hypertext Markup Language (HTML) in Web Publishing

Stands for "Hypertext Markup Language." HTML is the language which is used to create webpages. "Hypertext" refers to that of the hyperlinks that an HTML page may contain. "Markup language" refers to the way tags are used to define the page layout and the elements within the page.

Below is an example of the HTML used to define a basic webpage with that of a title and that of a single paragraph of text.

<!doctype html>

<html>

<head>

<title>TechTerms.com</title>

</head>

<body>

<p>This is an example of a paragraph in HTML.</p>

</body>

</html>

The first line defines what type of contents the document contains. "<!doctype html>" means the page is written in the HTML5. Properly formatted HTML pages should include <html>, <head>, and <body> tags, which are all included in that of the example above. The page title, metadata, and the links to referenced files are placed between that of the <head> tags. The actual contents of the page go between the <body> tags.

Over the past few decades the web has gone through many changes, but the fundamental language used to develop the webpages is HTML. Interestingly, when the websites have become more advanced and interactive, HTML has actually been simpler. If you compare the source of an HTML5 page with that of a similar page written in the HTML 4.01 or the XHTML 1.0, the HTML5 page would probably will contain the less code. This is because of the modern HTML which relies on cascading style sheets or the JavaScript to format nearly all of the elements within a single page.

NOTE: Many dynamic websites generate the webpages on-the-fly, using that of a server-side scripting language for instance PHP or ASP. However, even dynamic pages must be formatted using that of the HTML. Therefore, scripting languages often generate that of the HTML that is sent to your web browser.

9.7 Case study of Application

Automatically Converting Linear Text to Hypertext:

Automatically Converting Linear Text to Hypertext: Automatically changing digital documents, mainly a big quantity of linear free-text, to a suuctural non-linear fonn, e.G. Hypertext, is an increasing number of vital for some programs consisting of infonnation retrieval &#40;IR&#41;[SM84], office infonnation systems (OIS), etc. We describe an approach to reworking linear textual records from autonomous (free-text based totally) IR databases to hypertext, after which storing it in a relational As an experiment, CORDIS facts, a set of IR databases of the Commission o/the European Communities (CEC) inside the fonn oflinear free-textual content, has been transferred to the relational database system Sybase®l. The approach we've got taken, the gear used and the problems encountered are discussed.

1 Introduction

Electronic documents, such as digital consumer manuals, electronic mail, digital user inductions (e.G. README files), are used more and more to replace paper documents. Unfortunately, maximum of them are in the fonn of linear free-textual content. In many programs (OIS, IR, AI, etc.), demands are growing with a view to suture massive quantities of such linear electronic textual content into extra non-linear fonns, which can typically be categorized beneath the tenn: hype

The two main capabilities of hypertext are: machine-supponed links (within and between documents); and use 0/ windows to display a one-to-one correspondence with nodes in the database In this paper, we strain the first characteristic, i.E. a way to transfonn linear textual content to its node-link fonn and store it in a relational database.

The second feature is being implemented through the TORI [ZKM92) and MERIT [STI'92] tasks at GMD-IPSI, which aim to develop cognitive person interfaces for IR. The hassle of changing textual content to hypertext has best recently obtained attention within the literature. Most conversion tasks are either perfonned manually or handle best quite-suuctured text [FPS89-1 , FPS89-2, CNVW91, GI89].

The HEFn model (cf. [CNVW91j) proposes a sequence of six modular steps to attain conversion in a semi-automatic process: (1) textual content coaching; (2) node coaching; (3) indexing; (4) link creation; However, inside the case stated here, the textual fabric extracted from CORDIS is poorly suuctured, rather than fairly suuctured. Therefore, we use a modelling/changing strategy. For the conversion, a hierarchy-ahead approach is proposed and used, i.E. We combine the text instruction, node practise and hierarchy-based totally link advent in a single step.

The paper is prepared as follows: 1. Sybase® is a relalional database management machine of Sybase me. H. P. Frei et al. (eds.), Hypermedia© Springer-Verlag Berlin Heidelberg 1993 The remodeling of CORDIS statistics from linear textual content to hypertext is offered in Section 3. The data conversion is mentioned in Section 4. Future paintings is presented inside the remaining section.

2 CORDIS

CORDIS (Community Research and Development Information Service) provides statistics approximately EC Research and Technological Development (RTD) packages and related matters for companies The corresponding databases are named RID-CORDIS databases, e.G. RID-Programmes, RID-Projects, RID-Acronyms, RTD-Publications, etc. They are isolated and stored as inverted files. The data converted by using us is furnished by the CEC Brussels, and consists of RID-Acronyms, RID-Projects, RID-Programmes, RID-Publications, RID-Partners, etc. All facts is linear, and indexed by means of record number (preceded by using """"), and the content indices (preceded through "//"), as shown inside the Example 1. Example 1: The sample statistics from RTD-Projects are as follows, in which thereportindex is 'I' , the content material indexes are 'TIL', 'SIC', 'OBJ', etc.

References:

1. Multimedia : Computing, Communications & Applications by Ralf Steinmetz and Klara Nahrstedt, Pearson Ed.

2.            Multimedia Systems Design by Prabhat K. Andleigh & Kiran Thakrar, PHI.

3.            Principles of Multimedia by Parekh, TMH.